1. Field of the Invention
The present invention is related to a switching power controller, especially to a feedback terminal for the switching power controller. This feedback terminal is used for receiving a feedback signal and providing programming function for parameter setting.
2. Description of the Related Art
FIG. 1 shows a circuit diagram of a conventional power converter. As shown in FIG. 1, an inductor 10, a transistor 15, a rectifier 20 and a capacitor 25 develop a boost converter 30. One terminal of the inductor 10 receives an input voltage VIN. The other terminal of the inductor 10 is connected to an anode of the rectifier 20 and a drain terminal of the transistor 15. A source terminal of the transistor 15 is connected to a ground. A gate terminal of the transistor 15 receives a switching signal SW. A cathode of the rectifier 20 is connected to a positive terminal of the capacitor 25. The capacitor 25 with a negative terminal is connected to the ground. An output voltage VO is generated across the capacitor 25.
A controller (CNTR) 50 generates the switching signal SW at an output terminal SW to switch the transistor 15 for producing the output voltage Vo of the boost converter 30. A voltage divider developed by resistors 41 and 42 is coupled to the output voltage VO for generating a feedback signal VFB. The resistor 41 is connected to the output voltage VO and the resistor 42 in series. The resistor 42 is further connected to the ground. The feedback signal VFB is generated at a joint of the resistors 41 and 42, and is applied to a feedback terminal FB of the controller 50 for generating the switching signal SW and regulating the output voltage VO. A programmable signal SP is sensed on one end of a sensing resistor 40, which is connected to the controller 50 for parameter setting. The other end of the sensing resistor 40 is connected to the ground. Parameter settings are used to control a multi-phase power converter with master and slave controllers for higher output power.